Impact of an integrated process of hot pressurised liquid extraction–macroporous resin purification over the polyphenols, hydroxymethylfurfural and reducing sugars content of Vitis vinifera ‘Carménère’ pomace extracts

Abstract

Thermal degradation and generation of objectionable compounds such as hydroxymethylfurfural have been observed in hot pressurised water extraction of polyphenols. Addition of small amounts of ethanol can reduce process temperatures and retain extraction efficiencies. However, ethanol may reduce the recovery of polyphenols in the subsequent purification stage. The overall effect of increasing amounts of ethanol (0-15%) and reduced temperatures (90, 75, 60°C) in the extraction stage, as well as increasing amounts of ethanol in the desorption eluent (60-80%) were analysed in a combined hot pressurised liquid extraction-resin purification grape pomace polyphenols process for the first time. Without decreasing the polyphenols recovery (~24 mg GAE g À1 ), ethanol addition (15%) reduced the extraction temperature (from 130 to 90°C) which not only decreased the reducing sugar extraction (~25%) but also avoided the hydroxymethylfurfural generation in the extraction stage. Additionally, the combined hot pressurised liquid extraction-resin purification process preserved the proanthocyanidin oligomeric distribution and was selective to polyphenols. The operating conditions found for the combined process, efficiently produced purified polyphenols extracts (11 mg GAE g À1 ), free of hydroxymethylfurfural and reducing sugars.Carm en ere pomace polyphenols extracts M. S. Mariotti-Celis et al.

Effect of subcritical water processing on the extraction of compounds, composition, and functional properties of asparagus by‐product

“…In addition, they reported a drastic decrease in sucrose concentration from 112 °C explained by the hydrolysis reaction, forming glucose and fructose. Mariotti‐Celis et al () evaluated the extraction with pressurized hot water of sugars (glucose and fructose) at temperatures of 60–200 °C and verified degradation of these sugars above 130 °C where the formation of HMF occurred. Khajavi, Kimura, Oomori, Matsuno, and Adachi () reported the degradation of glucose in subcritical water at 180 °C with formation of different compounds, of which HMF was identified as the main product.…”

“…The efficiency of subcritical water treatment on sugar removal has previously been reported for apple (Plaza, Abrahamsson, & Turner, 2013) and grape (Mariotti-Celis et al, 2018) by-product. The thermal degradation of sugars can be caused by two main reaction pathways, with hydrolysis of sucrose, producing glucose, and fructose.…”

Glycerol as Alternative Co-Solvent for Water Extraction of Polyphenols from Carménère Pomace: Hot Pressurized Liquid Extraction and Computational Chemistry Calculations

“…A factorial experimental design was applied to determine the effect of extraction temperature and co-solvent during extraction on the global recovery of specific polyphenols which followed the methodology proposed by Mariotti-Celis et al [52]. In addition, mean and CV results were presented.…”

“…Polyphenol extracts were obtained from Carménère pomace using water-glycerol mixtures (15%, 32.5%, and 50%) at 90 • C, 120 • C, and 150 • C in a pressurized extraction device (ASE 150, Dionex, Sunnyvale, CA, USA). The experimental range of study, both for temperature and co-solvent level, was defined based on previous research [52,53] and prelaminar tests. The highest HPLE temperature (150 • C) was established considering the occurrence of HMF in the extracts.…”

“…However, high water temperatures (≥120 • C) significantly affect the chemical composition of the extracts due to polyphenol hydrolysis and formation of toxic compounds (Maillard compounds such as hydroxymethylfurfural, HMF) [46,47]. Co-solvents such as ethanol reduce the solvent polarity which can explain the significant improvement of polyphenols recovery and the considerable reduction in sugar extraction and HMF formation [48][49][50][51][52]. Glycerol, however, has been shown to be a better co-solvent than ethanol to recover polyphenols in conventional extractions; as far as we are aware there is no reported application of water-glycerol mixtures in HPLE.…”